The Arapaho (in French: Gens de Vache) tribe of Native Americans historically lived on the eastern plains of Colorado and Wyoming. They were close allies of the Cheyenne tribe and loosely aligned with the Sioux. Together with the Cheyenne they build an enclave of the Algonquian language in the West. The Northern Arapahos live on the Wind River Reservation north of Lander, Wyoming.

The Arapaho Indian tribe most likely lived in Minnesota and North Dakota. European expansion forced the Arapaho westward towards the area which is now Colorado, Wyoming, and Kansas. When the U.S. was placing Indians on reservations, one group of the Arapaho were sent to Oklahoma. There they shared the reservation with the Cheyenne and eventually the Cheyenne and Arapaho cultures grew similar.

They lived in teepees made of buffalo hide. Before they were sent to reservations, they migrated often chasing herds, so they had to design their teepees so that they could be transported easily. It is said that a whole village could pack up their homes and belongings and be ready to leave in only an hour.

They originally used dogs to pull travois with their belongings on them. When the Europeans came to North America, the Arapaho saw the Europeans' horses and realized that they could travel quicker and further with horses instead of dogs. They raided other Indian tribes, primarily the Pawnee and Comanche, to get the horses they needed.

Later on, they became great traders and often sold furs to other tribes and non-Indians. While nobody knows for sure, many think the name 'Arapaho' might have come from the Pawnee word for 'traders.'

The children often fished and hunted with their fathers for recreation. While they had more chores to do than present day Arapaho, they still had time to play games. They played many games, including one involving a netted hoop and a pole where they would try to throw their pole through the center of the net. It was much like the game of darts.

In present day, some Arapahos have gotten into the gaming or casino industry. A few of them own casinos, most notably the Arapaho Casino located in Wyoming.